Kiss your flask good-bye! How real-time data acquisition provides a superior solution over memory tools for high-temperature reservoirs.
Understanding True Reservoir Characteristics
Understanding the true characteristics of your reservoir is paramount for long-term success and field development. As we always say,
You can't manage what you don't measure!
Real-time downhole data acquisition is one of the fastest-growing sectors in the energy business. Why? The results of transient pressure tests never fail to surprise stakeholders.
Too often memory tools are pulled too early, with inconclusive results leaving engineers to ponder what would happen if they had only extended the test by a couple of extra hours, days, or sometimes longer. We here at GEO PSI see this often with fracture injectivity and fall-off tests which have significant cots and economic implications. Because of this we can not emphasize enough the importance of collecting high-quality test data.
Quality Test Data For High-Temp
This is even more important for ultra-high temperature applications such as geothermal reservoirs. Even the best electronics found in memory tools do not work well past 200°C (392°F).
Traditionally the memory tools are placed in a thermal vacuum flask to extend their run time. The typical run time life of a flask is 4 to 8 hours, and oftentimes in the real world, the actual run time is even less. Better flasks use nitrogen and helium, but even they still have a very limited run time. They are difficult to set up and the failure rate is very high. Not only that, but the flask also distorts the temperature data that’s being collected, which is an extremely important characteristic of geothermal reservoir development.
Pro's & Con's Of Flask Memory Tools
Pros
Cons
- Initial tests are cheaper than real-time downhole data acquisition.
- Short downhole run time of only a few hours. The reservoir test may still be inclusive when the gauges are pulled. You are not guaranteed to get the data that you need. If something goes wrong with the rig while the flask is downhole, the money is wasted.
- Horrifically unreliable. Electronics are vulnerable to elevated temperature. Memory is often corrupted and not retrievable.
- The clock (time records) of memory tools run inconsistent as the internal flask temperature increases which makes it difficult to synchronize pressure events and time.
- The flask prevents the memory tools from recording accurate temperature which also effects the accuracy of the pressure measurement.
- Most memory tool rental companies will charge clients for new memory tool replacement after the test is complete, which increases the cost of the test significantly.
- Memory tools can be very dangerous at high-temperatures requiring volatile high-discharge lithium-ion batteries. The higher the temperature the less predictable the run life is and the more dangerous the battery pack becomes. At a certain temperature, the lithium can explode potentially causing damage or bodily harm.
A Superior Solution
The superior solution is to use our innovative GEOTRU real-time downhole pressure and temperature data acquisition systems.
We have a proven track record of collecting downhole data at temperatures up to 316°C (600°F) continuously for years at a time. The technology was developed for Canadian oil sand steam wells and has proven to be 100% successful.
We use sensor technology originally developed for US military, space, and aeronautical industries to measure critical pressure and temperature data. There are no downhole electronics in our gauges. Instead, the electronics are located at the surface and attached to our industry leading 4mm downhole cable that is temperature rated to 316°C (600°F).
The gauges are fully welded and guaranteed to be leak-free through our rigorous quality controls. We are API and ISO certified and do approximately 150 real-time downhole data projects per month.
Pro's & Con's Of Real-Time GEOTRU Gauges
Pros
Cons
- Pressure and Temperature data is delivered in real-time and collected at the surface. The test duration is determined by the reservoir data, not the longevity of the flask or operating life of the memory tool or batteries. You are guaranteed to get the data that you need.
- Higher up-front cost than memory tool flask.
- Unparalleled reliability. Our gauges have a proven track record with 100% success rate.
- Time synchronized data. Since the electronics are at the surface the clock is real-time. Sample rate as fast as once per second.
- High-quality pressure and temperature data. No flask to distort temperature data. Accuracy is +/- 0.05% full scale with resolution of 0.01 psi.
- Our systems are re-useable offering long-term value. Once the system is pulled from the well it can be re-used in other wells or installed as a permanent pressure temperature solution.
- No dangerous goods or lithium batteries which can become volatile at higher temperatures.
- We transmit test data to our secure cloud service where it can be viewed by stakeholders through any PC, Tablet, or Smart Phone in real-time.
Conclusion
Flasks were useful for years when there was no alternative. However, our GEOTRU real-time data collection system is the best value for high-temperature well tests and provides an incredible long term asset for completion. The value of the extra up-front expenditure is worth it. You can collect more data, run the test longer, and re-use the equipment for years to come. The flask may be cheaper, but there are risks involved and you may not get the data that you need.
We can provide hardware and/or install reliable high-temperature downhole monitoring systems the following ways:
- Through Tubing Suspended (Wireline)
- Tubing Conveyed
- Casing Conveyed (Cemented / Grouted in sensors)
We here at GEO PSI deliver long-term performance at reasonable prices. Contact us today if you would like to know more!
Through Tubing Suspended (Wireline)
Figure 1: Through Tubing Suspended (Wireline) System
Tubing Conveyed
Figure 2: Tubing Conveyed System
Casing Conveyed (Cemented / Grouted in sensors)
Figure 3: Casing Conveyed (Cemented / Grouted in sensors) Systems
